I tested the Gigabyte 3D Galaxy against a modest, inexpensive but very efficient air cooler from GlacialTech, Igloo 5100PWM, that was working at its maximum speed of 3600rpm. With all its positive qualities, the Igloo 5100PWM is too loud at its highest speed, I should say. If you are not satisfied with the comparison of an air cooler with a liquid cooling system, you can just evaluate the efficiency of the Gigabyte 3D Galaxy by its cooling a Prescott-core processor overclocked to 4.1GHz. But first I want to tell you about the noise from the tested system.
The pump and the water-block fan work noiselessly inside the system case (the declared noise is 20dBA and 19dBA, respectively). When the side panel was open, I could hear the sound of the pump against the noise of the otherwise rather quiet system case, while the fan was still inaudible. As for the noise from the 120mm fan, everything is in your hands. It is absolutely silent at 1200rpm, and the whole computer becomes almost silent (I say “almost” since you can still perceive the general low hum of the system case). Steadily giving more speed to the fan, I found that it remained silent up to 1600-1700rpm. After that mark you can hear its hum, but it doesn’t become annoying until 1900-2000rpm. As for the maximum speed, the 120mm fan is loud at 2600rpm, but is still quieter than the Igloo 5100PWM at 3600rpm! Since a second argument in favor of liquid cooling is quiet operation, I tested the system at the quiet 1650rpm as a speed you are likely to use (the system was also tested at the min and max speed of the heatsink fan).
I performed the first cycle of tests when the processor worked at its default 3200MHz frequency and 1.3625V voltage. Here are the numbers:
Water does it! The 3D Galaxy cools the CPU by 11°C better than the Igloo 5100PWM does, their levels of noise being incomparable. At the normal Super PI load the liquid-cooling system is 3°C worse the roaring air cooler in the idle mode! Note that the efficiency of the Gigabyte 3D Galaxy is increasing linearly under S&M as the speed of the heatsink fan grows.
Now I increase the CPU voltage and frequency and rerun the tests once again:
The Igloo 5100PWM stopped just one step short of Throttling – the maximum 3600rpm speed does not help anymore. The 3D Galaxy is, on the contrary, all right: 54°C under S&M, 49°C under the two copies of Super PI, and 37°C in the idle mode. A person who has only dealt with air cooling may find these numbers miraculous for a Prescott core overclocked to 4.1GHz. Talking about the 3D Galaxy alone at the maximum 2600rpm I think that 45°C under Super PI is excellent for a “pre-Freon” system with such a hot processor.